Teddit is misspelled Reddit, it is an alternative frontend for the popular social network. It also offers viewing of Reddit posts for users who are not signed up to, unlike the original reddit which makes you sign up if you want to look around.
Teddit also markets itself as more secure for users, than connecting directly via reddit, with no tracking, information collecting, and faster reloading.
Like Teddit for Reddit, there are alternative front ends for other social networks, like Nitter for Twitter, Piped for YouTube, etc.